1. Field of the Invention
This invention refers to a process for the determination of a longitudinal equivalent reactance in an electric power supply line with reference to a measuring point, particularly at the connecting point of a generator in a supply line. The invention further refers to a system for the determination of the phase angle of a system voltage at a measuring point as it can especially be used for the implementation of the above-mentioned process.
2. Description of the Prior Art
For the running and controlling of electric high-efficiency power lines, and particularly for the control of generators operating in a power system, certain reactance values of the supply line are required as parameter dimensions or signals. This includes the longitudinal equivalent reactance with reference to a measuring point, i.e. the longitudinal reactance between the system voltage at the measuring point, on the one hand, and a system voltage to be assumed as amplitude and phase-fixed which, therefore, limits the system section coupled with the respective measuring point or with the generator connected here. It is, in this instance, essentially a question of the inner reactance of a substitute source representing the mentioned supply line section with the given, fixed supply line voltage as impressed source voltage. Since it is a question of a longitudinal reactance, the resistances and capacitances can, in general, be neglected vis-a-vis the inductances which justifies the sole treatment of an equivalent reactance.
The value of the longitudinal equivalent reactance of a power line with reference to a measured point can, in principle, be determined from the entire power line configuration by taking into consideration the respective load conditions. However, such a determination is not applicable in practice during operation because the load condition and also the power line configuration are subjected to more or less important, current changes and, for this reason, an extensive measuring and data transmission system would be a prerequisite.